Baltic Sea
The Baltic Sea is a brackish inland sea in northern Europe, connected to the North Sea and Atlantic Ocean through the Danish straits.
Danish straits: The narrow waterways linking the Baltic Sea with the Kattegat and, beyond it, the North Sea. These passages regulate the Baltic Sea’s exchange of water and salt with the ocean.
Baltic Sea basin: The connected marine basins and straits that make up the Baltic Sea. Its shallow sub-basins shape circulation, habitats, and the distribution of salinity.
Baltic Sea shipping: Commercial and passenger maritime transport across the Baltic Sea and its ports. The sea carries substantial regional trade despite winter ice and sensitive coastal waters.
Baltic Sea dead zones: Seafloor regions where oxygen depletion prevents most marine animals from living. They are a visible ecological consequence of persistent hypoxia in deep waters.
Hanseatic League: A medieval and early modern commercial alliance of towns and merchants in northern Europe. Its trading network connected Baltic ports and helped shape the region’s urban history.
Brackish water: Water with salinity between that of freshwater and typical seawater. River inflow and limited ocean exchange make the Baltic Sea brackish.
Kattegat: A sea between Denmark and Sweden connecting the Baltic approaches with the Skagerrak. It forms an intermediate waterway between the Danish straits and the North Sea.
Baltic Sea fisheries: The harvesting and management of fish populations in the Baltic Sea. Fisheries depend on changing stocks of species such as herring, sprat, and cod.
Baltic Sea algal blooms: Rapid growths of algae and cyanobacteria in Baltic Sea waters. Nutrient pollution and warm, calm conditions can trigger extensive blooms.
Viking Age: A period of Scandinavian maritime expansion, trade, and raiding, conventionally dated from the late eighth to the eleventh century. Baltic routes linked Scandinavian communities with settlements and markets across northern Europe.